Accurate measurements of surface profiles are useful in a wide range of applications. An example application is measuring surface profiles inside the bores of casing or production tubing in wellbores (e.g. oil and gas wells). Surface profile measurements can help to identify problems such as corrosion, wear and the like.
Some surface profilers operate using optical triangulation. Examples of surface profilers that operate using the principle of optical triangulation are described in commonly owned US patent Keightley et al. 8035823 issued on 11 Oct. 2011, which is hereby incorporated herein by reference for all purposes as if fully set out herein.
Apparatus for some downhole applications must be capable of operating in harsh environmental conditions of pressure and/or temperature. Pressures in some wellbores can be hundreds or thousands of pounds per square inch. Temperatures in some wellbores can exceed 150° C.
References describing apparatus for surface profiling include:                U.S. Pat. No. 4,983,043;        U.S. Pat. No. 5,615,003;        U.S. Pat. No. 5,663,758;        U.S. Pat. No. 6,580,449;        U.S. Pat. No. 7,751,038;        U.S. Pat. No. 7,884,951;        U.S. Pat. No. 8,528,668;        U.S. Pat. No. 8,841,603;        U.S. Pat. No. 8,842,273;        U.S. Pat. No. 8,925,213;        U.S. Pat. No. 9,062,531;        
There remains a need for improved systems and methods for making surface profile measurements.